The present invention pertains to an autonomous vehicle having a distance measuring sensor that measures the distance to an object without touching said object.
As one example of a conventional distance measuring sensor, FIG. 9 shows the construction of a distance measuring sensor using the infrared active method. The ray of infrared light that is output from infrared LED 401, as detection waves output toward the object for the purpose of distance measurement, is projected onto object 403, which is the object of measurement, via projection lens 402. Part of the infrared ray that is reflected irregularly by object 403 forms an image on light receiving element 405 via condenser lens 404. In other words, this distance measuring sensor measures the distance to the object based on the location of the reflected light which forms an image on light receiving element 405 using the principle of triangulation. Conventional distance measuring sensors periodically perform distance measurement using a prescribed period by being driven at prescribed constant intervals.
Now, where the distance measuring sensor described above is mounted on an autonomous vehicle, when the autonomous vehicle moves at a high speed, the distance over which the autonomous vehicle travels between the previous distance measurement session and the current distance measurement session becomes large, which prevents the successful performance of accurate distance measurement. Therefore, one solution to this problem is to periodically perform distance measurement using the smallest possible period regardless of the state of the movement of the autonomous vehicle. However, because with this method distance measurement is carried out using the smallest possible period even when a larger distance measurement period would not pose a problem, such as when the distance to the object is short or when the autonomous vehicle is moving slowly or not at all, for example, detection waves (infrared ray) output toward the object for the purpose of distance measurement are output to an unnecessary degree, and excess power is consumed.